CGYrjrr,ment. 


Circular   no    50.  Second   Series    Reviseo  Edition         i 

United  States  Department  of  Aunculturr, 

BUREAU    OK     ENTOMOLOGY, 

|i>  » \N  AKl>  BuNM. 

WHITE    WT. 

1 1  i !■■  -   Koll.). 

0,   L.   M  LBJ  v 

I         i  Chief  ii  of  Ch 

■  occurring  in  houses  ie  capable  of  doing  great 
the  our  under  consideration.  Its  injuries  are  often  hidden  until  the 
damage  is  beyond  repair,  and  ae  it  affects  the  integrity  of  the  building 
itself  ae  well  as  it-  contents,  the  importance  of  the  insect  becomes  very 
evident i     Fortunately  it  ia  not  often  present  in  the  North  in  houses, 


■ 

but  as  the  Tropica  are  approached  the  injuries  from  it  in  dwelling 
other  structures  oi  wood  are  of  common  experience  and  often  of  th<' 
most   Berious  nature,   causing   thi    Budden   crumbling  of  l>ri.l^«~  and 
wharves  and  settling  ol  floors  or  buildings. 

The  term  "white  ant,"  by  whicb  this  insect  ie  universally  known,  ia 
entirely  inappropriate  in  -  -  it  indicates  any  relation-hip  with  the 

true  ante.     Strictly  speaking,  the  white  ant  is  not  an  ant,  but  a  neurop- 
teroid  insect  belonging  to  the  ord  -    dlied  to  the  hook 

ind  -tour  flies.  The  only  analogy  with  ants  ia  in  superficial  resem- 
blance and  in  the  social  habita  of  thi  »ups,  in  whi<  -imi- 
lurit  The  popular  acquaintani  a  with  the  termite  or  white  ant 
is  mainly  derived  from  witnessing  ite  nuptial  spring  flight,  when  the 
small  brown,  ant-like  creatures  with  I  ite  wings 
from  cracks  in  the  ground  or  from  crevice-  in  buildings,  Bwarmu 
sometimes   in  enormous  numbers,  so  that   they  may  often  be  swept  up 


by  the  quart.  These  winged  individuals  are  not  the  ones  which  do  the 
damage,  but  are  the  colonizing  form.  The  real  depredators  are  soft- 
bodied,  large-headed,  milky  white  insects,  less  than  a  quarter  of  an  inch 
in  length,  which  may  often  be  found  in  numbers  under  rotting  boards 
or  in  decaying  stumps.  These  last  are  the  workers  and  soldiers  (rig.  4, 
c  and  d) ,  and  constitute  the  bulk  of  the  colony  for  most  of  the  year,  the 
winged  migrating  forms,  consisting  of  the  sexed  individuals,  appearing 
normally  only  once  a  year,  usually  in  April  or  early  in  May. 

The  white  ants  present,  in  an  entirely  distinct  order  of  insects, 
another  of  those  most  curious  problems  of  communal  societies  which 
find  so  many  examples  among  the  ants,  bees,  and  wasps.  A  colonj'  of 
white  ants  includes  workers,  soldiers,  the  young  of  the  various  forms, 
and,  at  the  proper  season  of  the  year,  the  winged  males  and  females ; 
also  a  single  parent  pair,  the  specially  developed  king  and  queen.  In 
the  case  of  the  common  white  ant  of  this  country  (Termes  flavipes),  the 
fully  developed  queen  or  mother  of  the  colony,  swollen  to  great  size  by 
her  enormous  ovary  development,  and  her  consort,  the  fully  developed 
hut  much  smaller  king  or  male,  have  never  been  found  in  the  white  ant 
communities,  and  this  in  spite  of  the  great  numbers  of  the  flying  stage  of 
both  sexes  that  appear  every  spring.  The  soldiers  or  workers  are  degraded 
or  undeveloped  individuals  of  both  sexes,  differing  in  this  respect  from 
ants  and  bees,  in  which  the  workers  are  all  undeveloped  females. 

The  economy  of  the  termites  is  almost  exactly  analogous  to  that  of 
the  ants  and  bees.  The  workers  attend  to  all  the  duties  of  the  colony, 
make  the  excavations,  build  the  nests,  care  for  the  young,  and  protect 
and  minister  to  the  wants  of  the  queen  or  mother  ant.  In  this  they  art- 
assisted  somewhat  by  the  soldiers,  whose  duty,  however,  is  also  pro- 
tective, their  enormous  development  of  head  and  jaws  indicating  their 
role  as  the  fighters  or  defenders  of  the  colony.  Both  the  workers  and 
soldiers  are  blind.  The  colonizing  individuals  differ  from  the  others  in 
being  fully  developed  sexually  and  in  the  possession  of  very  long  wings, 
which  normally  lie  flat  over  each  other,  the  upper  wings  concealing  the 
lower  and  both  projecting  beyond  the  abdomen.  These  wings  have  a 
very  peculiar  suture  near  the  base,  where  they  can  he  readily  broken 
off,  leaving  mere  stumps.  At  the  time  of  the  spring  (light  the  winged 
individuals  emerge  from  the  colony  very  rapidly,  frequently  swarming 
in  clouds  out  of  doors,  and  after  a  short  flight  fall  to  the  "round  and 
very  soon  succeed  in  breaking  oft'  their  long  clumsy  wings  at  the  suture 
referred  to.  In  this  swarming  or  nuptial  flight  they  come  out  in  pairs. 
and  under  favorable  conditions  each  pair  might  become  especially 
developed,  as  described  above,  and  establish  a  new  colony,  but  in  point 
of  fact  this  probably  rarely  happens.  Tiny  are  wreak  flyers,  clumsy,  and 
not  capable  of  extensive  locomotion  on  foot,  and  are  promptly  preyed 
upon  and  destroyed  by  many  insectivorous  animals,  so  that  rarely  indeed 
do  any  of  the  individuals  escape. 


3 


Theoretically,  it  one  ol  these  pain  succeeded  in  finding  a  decaying 
stimip  or  other  Buitable  location  ;tt  hand,  they  would  enter  it,  and  the 
king  and  queen,  being  both  active,  would  attend  to  the  want-  of  the 
new  colony  and  superintend  the  rearing  of  the  tirst  1  >r« ►< >.  1  of  workers 
and  Boldiers,  which  would  then  assume  the  laborious  duties  <>f  the 
youDg  colony.  Thereafter  the  queen,  being  constantly  and  liberally 
led  and  kept  absolutely  inactive,  would  increase  immensely,  her  abdo- 
men becoming  many  hundred  times  its  original  size.  She  would  prac- 
tically lose  the  power  of  locomotion  and  become  a  men  lying 
machine  of  enormous  capacity.  Allied  Bpeciee  whose  habits  have  been 
studied  in  this  particular  indicate   an   egg-laying   rate  of  60  per  minute, 

or  something  like  80,000  per  day. 

In  the  absence  of  a  queen,  however,  white  ants  are  able  to  develop 
from  a  very  young  larva  or  nymph  of  what  would  otherwise  become 

a  winged  female  what  is  known  as  a  supplementary  queen,  which  is 

never  winged  and  never  leaves   the  colons.      This  supplementary  queen 


■  i.  Head  of  winged  female  viewed  from  above;  b,  same  from  below,  »ith 

moii'  i.  ■!  out      I  itltiI    oris  ! 

(fig.  1.  "),  for  the  discovery  of  which  we  are  indebted  to  the  late  II.  (I. 
Hubbard,  is  .-mailer  than  the  pert  I  queen,  hut  subserves  all  the 

needs  of  the  colony  in  the  matter  of  egg  laying,  and  is  the  only  parent 
■  so  far  found  in  the  nestfl  <>l  the  common  white  ant  in  this  coun- 
try. Whether  a  true  queen  exists  or  not  is,  therefore,  open  to  question; 
if  not.  all  the  individuals  which  escape  in  the  spring  and  summer  migra- 
tions must  perish,  and  this  Bwarming  would,  therefore,  have  to  be  con- 
sidered a  mere  survival  of  a  once  useful  feature  in  the  economy  of  this 
insect,  now  no  longer,  or  rarely,  of  service. 

The  normal  method  of  the  formation  of  new  colonies  is  probably 
by  the  mere  division  or  splitting  up  of  old  ones — their  galleries  and 
branch  colonies  extending  great  distances  from  the  home  colony — or 
through  the  carrying  of  infested  logs  Or  timbers  from  one  point  to  another. 

These  curious  insects  have  a  very  simple  development.  There  is 
scarcely  any  metamorphosis,  the  change  from  the  young  larva  to  the 
adult  being  very  gradual  and  without  any  marked  difference  in  struc- 
ture. They  feed  on  decaying  wood  or  vegetable  matter  of  any  sort. 
and  are  able   to  carry   their   excavations   into   any  timhers   which  are 


moistened,  or  into  furniture,  books,  or  papers  stored  in  rooms  which 
are  at  all  moist.  Their  food  is  the  finely  divided  material  into  which 
they  bore,  and  from  which  they  seem  able  to  extract  a  certain  amount 
nf  nourishment,  probably  from  the  molds  and  ferments  generated  in  the 
moistened  vegetable  substance,  since  they  redevour  the  same  material 
several  times.  Bearing  out  this  theory,  tropical  species  are  known  to 
grow  mushroom  beds  artificially  on  the  product  of  which  they  largely 
subsist.  The  white  ants  are  also  somewhat  cannibalistic,  and  will 
devour  the  superfluous  members  of  the  colom-  without  compunction, 
and  they  normally  consume  all  dead  individuals,  cast  skins,  and  other 
refuse  material.  They  are  capable  also  of  exuding  a  sort  of  nectar, 
which  is  used  to  feed  the  young  and  the  royal  pair,  and  which  they 
also  generously  give  to  one  another. 

All  except  the  migrating  winged  forms  are  incapable  of  enduring  full 
sunlight,  and  the  soft,  delicate  bodies  of  the  workers,  soldiers,  and 
young  rapidly  shrivel  when  exposed.  In  all  their  operations,  therefore, 
they  carefully  conceal  themselves,  and  in  their  mining  of  timbers  or 
books  and  papers  the  surface  is  always  left  intact ;  whenever  it  is  neces- 
sary for  them  to  extend  their  colonies  it  is  done  only  under  the  protection 
of  covered  runways,  which  they  construct  of  particles  of  comminuted 
wood  or  little  pellets  of  excrement.  In  this  way  the  damage  which  they 
are  doing  is  often  entirely  hidden,  and  not  until  furniture  breaks  down 
or  the  underpinning  and  timbers  of  houses  or  floors  yield  is  the  injury 
recognized.  The  swarming  of  winged  individuals  in  the  earl}*  summer, 
if  in  or  about  houses,  is  an  indication  of  their  injurious  presence  and  war- 
rants an  immediate  investigation  to  prevent  serious  damage  later  on. 

The  common  termite  of  America  is  very  widespread,  occurring  from 
the  Atlantic  to  the  Pacific  and  from  Canada  southward  to  the  Gulf. 
It  has  been  found  on  the  mountains  of  Colorado  and  Washington 
at  a  height  of  over  7,000  feet.  In  prairie  regions  it  may  often  be  seen 
during  the  swarming  season  issuing  from  the  ground  at  frequent 
intervals  over  large  pasture  tracts,  where  it  must  feed  on  the  roots  of 
grass  and  other  herbage.  It  has  also  been  carried  to  other  countries  and 
is  a  common  and  often  very  injurious  enemy  of  buildings  and  libraries 
in  Europe.  A  closely  allied  and  equally  injurious  European  species 
(Termes  lucifugus)  has  also  been  brought  to  this  country  in  exchange 
for  ours,  but  compared  with  our  own  species  it  is  somewhat  rare  though 
already  widely  distributed.  In  this  country  serious  damage  to  build- 
ings from  the  white  ant  has  not  been  of  common  occurrence,  especially 
in  the  North,  except  in  some  notable  instances.  In  Europe  our  species 
has  caused  greater  damage,  and  sonic  years  ago  gained  access  to  one  of 
the  Imperial  hothouses  at  Vienna,  and  in  spite  of  all  efforts  to  save  the 
building  it  was  necessary  ultimately  to  tear  it  down  and  replace  it  with 
an  iron  structure.  In  this  country  instances  are  on  record  of  very 
serious  damage  to  books  and  papers.     An  accumulation  of  books  and 


papers  belonging  to  the  State  of  Illinois  was  thoroughly  ruined  bytheir 
attacks.  A  Bchool  library  in  South  Carolina,  which  had  been  lefl  i 
for  the  Bummer,  was  found  on  being  opened  in  the  autumn  to  I"-  com 
pletely  eaten  out  and  rendered  valueless.  Ln  the  Department  of  Agri- 
culture  an  accumulation  of  records  and  documents  Btored  in  a  vault  Dot 
perfect I3  dry,  and  allowed  to  remain  undisturbed  for  several  years,  on 
examination  proved  to  be  thoroughly  mined  and  ruined  by  white  ants. 

Humboldt,  on  the  authority  of  Hagen,  accounts  for  the  raritj  of  old  l k- 

in  N.u  Spain  by  the  frequency  of  the  destructive  work  of  these  insi 

Numerous  instances  of  damage  to  underpinning  <>t'  buildings  and  to 
timbers  are  also  on  record.  The  flooring  of  one  of  the  largest  sections 
of  the  United  State-  National  Museum  was  for  some  years  annually 
undermined  and  weakened  by  a  very  large  colony  of  these  pests  which 
could  not  1"'  located,  and  finally  the 
authorities  Bolved  the  problem  byre- 
placing  the  wood  floor  w ith  one  of 
cement.  A  few  years  ago  it  was  found 
necessary  to  tear  down  and  rebuild 
three  frame  buildings  in  Washington 
in  consequence  of  the  work  of  this 
insidious  foe,  and  renewal  of  founda- 
tion timbers  or  replacing  with  arti- 
ficial stone  IS  often  called  for. 

Damage  of  the  sort  mentioned  has 
occurred  as  far  north  as  Boston,  but,     no.  s.-T$rme*na  wiy  hatched 

jtated,   greatly  increases  as  one       hirva-  '•■  s:,,n"  from  be,ow;  c- CL' 

enlarct'l    original). 

approaches  the  Tropics,   where    the 

warmth  and  moisture  are  especially  suited  to  the  development  and 
multiplication  of  this  insect.  There  houses  and  furniture  are  never  safe 
from  attack.  The  sudden  crumbling  into  masses  of  dust  of  chairs. 
desks,  or  other  furniture,  and  the  mining  and  destruction  of  collections 
of  hooks  and  papers,  are  matter-  of  common  experience,  very  little  hint 
of  the  damage  being  given  by  a  surface  inspection,  even  when  the 
interior  of  timbers  or  boards  has  been  thoroughly  eaten  out,  leaving  a 

mere  shell. 

While  confining  their  work  almost  solely  to  moistened  or  decaying 
timbers  or  vegetable  material  of  any  sort,  and  books  and  papers  thai 
are  somewhat  moist,  termites  are  known  to  work  also  in  living  I 
carrying  their  mines  through  the  moist  and  nearly  dead  heart  wood.  In 
this  way  some  valuable  trees  in  Boston  were  so  injured  a-  to  make 
their  removal  nece.-sary.  In  Florida  these  insects  have  been  the  cause  of 
considerable  damage  to  newly  planted  groves  of  orange  trees,  working 
around  the  crown.-  and  in  the  roots.  The  damage  lias  been  chiefly 
t  clearings  where  a  good  deal  of  rotten  wood  still  remained 
in  the  soil,  tlrs  accounting  for  their  presence.      These  insects  are  - 


times  also  the  occasion  of  considerable  injury  to  other  trees ;  and  quite 
recently  the  writer  received  information  of  injurious  attacks  on  pecan, 
chestnut,  and  walnut  trees  at  Augusta,  Ga.  They  also  cause  loss  in 
conservatories,  attacking  cuttings  and  the  roots  of  plants.  Such  injuries 
have  been  brought  to  our  notice  several  times  by  florists,  and  Mr. 
Chittenden,  of  this  office,  informs  me  that  white  ants  are  apt  to  attack 
the  large  stems  of  herbaceous  plants  like  geraniums.  In  greenhouses 
the  termites  usually  originate  in  the  more  or  less  decayed  woodwork  of 
the  building  itself  or  the  plant  benches,  and  they  have  even  been  found 


Fia.  4.—Tcrmes  flavipes:  a.  Queen;  b,  nymph  of  winded  female:  c,  worker;  <l,  soldier. 

enlarged  (original). 


All 


working  in  label  sticks,  the  removal  of  which  gave  relief  from  the  dam- 
age done  to  plants.  In  one  instance,  also,  the  termites,  coming  from 
the  wooden  benches,  entered  potted  plants  through  the  drain  hole  of 
the  pots.  In  prairie  regions  their  work  is  necessarily  on  the  roots  and 
tubers  of  plants  or  the  stems  of  grasses  or  other  low-growing  plants. 

A  very  common  form  of  injury  to  potatoes  growing  in  rich  soil  or 
where  there  is  a  considerable  quantity  of  decaying  vegetable  matter  has 
often  been  noted,  and  the  cause  for  it  has  been  obscure  or  assigned  to 
insects  innocent  of  the  damage.  That  the  white  ant  is  the  culprit  in 
this  case  was  discovered  by  Mr.  F.  A.  Marlatt,  who  describes  the  injury 


to  the  tubers  as  having  the  form  ol  s<  ars  or  pits  covering  the  bui 
die  pits  varying  in  Bhape  from  irregular  holes  to  long,  irregulai  i 
tions  sometimes  extending  far  into  the  potato,   bul   commonly  t"  a 
depth  i>f  from  ;m  eighth  to  a  fourth  of  an  inch.     In  all  cases  th<  Be  pits 
axe  more  or  l<  as  overhung  and  covered  by  the  dead  and  dying  -km.  and 
are  also  lined  with  the  cellular  tissue  of  potato,  Bhowing  thai  the  ii 
cares  most  for  the  starch  and  water  of  the  tuber.     Such  damage  may 
occur  not  only  in  soil  rich  in  vegetable  matter  but  also  in  newly  cl< 
■oil  or  soil  containing  the  loose  and  decayed  portions  of  trees,  and  in 
the  instance  cited  above  was  in  .-oil  from  which  an  old  apple  orch  ird 
had  recently  been  cleared. 

rici:\  r.s  1 1\ 

White  ant  infestation  of  houses  is  probably  always  from  an  outside 
source.  The  i|iiecn  chamber  ami  breeding  center  of  the  colony  may  lie 
and  usually  is  remote  from  the  building,  but  the  workers  construe! 
minute  galleries  or  tunnels  through  the  ground  and  go  long  distances  in 
search  of  moist  and  decaying  wood.  Their  entrance  to  buildings  is 
gained  through  Borne  of  theee  .-oil  channels  by  way  of  wooden  bean 
joists  sunk  in  concrete  in  the  foundations  of  the  buildings,  or  the  -nil- 
ports  of  porches  or  other  parts  of  the  edifice  VI  hich  come  in  contact  with 
the  soil.  The  fact  that  the  beams  or  joists  of  the  basement  are  entirely 
inclosed  or  imbedded  in  concrete  is  only  a  partial  protection.  In  the 
settling  of  the  house  concrete  i-  alm<  -t  Bure  to  crack,  allowing  avenui  - 
of  ingress,  and  the  beams  and  joists  put  down  in  the  moist  material 
soon  partially  decay  ami  become  exceptionally  good  breeding  pi 
from  such  beams  the  white  ants  carry  their  burrows  tip  through  the 
timbers  to  the  first  and  even  second  floors.  To  be  on  the  Bate  side, 
therefore,  the  foundations  of  buildings  should  lie  entirely  of  hrick.  -tone. 
or  concrete,  including  the  basement  floor,  and  especially  should  this 
method  oi  construction  he  followed  in  t r< >id<-;i  1  and  subtropical  regions. 

In  the  case  of  old  buildings  not  constructed  in  this  way  considerable 
protection  can  he  gained  by  surrounding  them  with  clear  -pier-  and 
graveled  or  asphalted  walk-,  and  looking  after  the  prompt  removal  of 
any  decaying  stump-  or  partially  rotted  posts  that  may  be  in  adjac<  nt 
grounds.  Complete  dryness  i^  an  important  means  ol  rendering  build- 
irom  attack.  Hooks  and  valuable  documents  should  not  he 
packed  away  in  unventilated  chambers  where  they  may  become  i 
and  middy,  and  are  then  particularly  Bubject  to  attack  by  white  ants, 
winch  are  very  likely  to  be  present  in  old  buildings  even  though  their 
work  has  not  been  sufficient  to  l>ring  them  into  -|  .  .  .  ,1  notice. 

Impregnation    with  creosote   renders   « 1   comparatively    immune 

from  the  attacks   of   white    ant-,  and    in    i  .here    injury   is   to  he 

anticipated  it  would  be  well  to  use  wood  so  treated  wherever  it  comes 
in  contact  with  the  ground.  A  heavy  coating  of  foundation  timbers 
with  tar  is  often  resorted   to.  and   this   protects  the  wo 


UNIVERSITY  OF  FLORIDA 


8  3  1262  09216  4804 

coating  is  intact.  Certain  woods,  also,  are  fairly  immune,  and  of  these 
the  redwood  of  California  is  most  accessible  and  seems  to  have  a  good 
record.  Capt.  Geo.  P.  Ahearn,  U.  S.  Army,  reports  that  California 
redwood  has  been  used  for  more  than  twenty-five  years  in  the  Philip- 
pines, and  has  never  been  known  to  he  injured  by  white  ants.  Its  use 
in  Manila  is  very  general,  especially  for  the  construction  of  cabinets, 
filing  cases,  etc.,  where  it  is  desirable  to  protect  valuable  papers  from 
these  insects. 

In  the  Tropics  household  furniture,  such  as  stands  and  bureaus,  not  in 
daily  use  can  be  protected  by  placing  the  legs  in  small  vessels  contain- 
ing oil.  Furniture,  furthermore,  should  not  lean  against  or  touch  walls, 
especially  in  houses  of  wood,  and  frequent  examinations  should  be 
made  of  libraries  and  of  stored  papers. 

REMEDIES. 

The  presence  of  flying  termites  in  a  building  at  any  time  in  the  spring 
or  summer  should  be  followed  immediately  by  a  prompt  investigation 
to  determine  the  extent  of  the  infestation  and  the  possibilities  of  fur- 
ther damage.  The  point  of  emergence  of  winged  individuals  may 
approximately,  though  not  always,  indicate  the  location  of  the  infested 
timbers,  and  if  these  can  be  replaced  injury  may  be  checked,  or,  under 
favorable  circumstances,  stopped.  In  some  cases  thorough  and  repeated 
drenching  of  infested  timbers,  where  accessible,  with  kerosene  or  some 
other  petroleum  oil  will  afford  relief,  but  probably  will  not  stop  entirely 
the  work  of  the  termites,  which,  as  indicated  under  the  heading  of 
"Preventives,"  are  constantly  recruited  from  some  central  colony 
probably  distant  from  the  building.  The  destruction  of  winged  indi- 
viduals as  they  emerge  is  of  no  value  whatever.  Where  the  injury  is 
confined  to  books  and  papers  or  exposed  woodwork  and  furniture, 
hydrocyanic-acid  gas  fumigation  is  to  be  recommended,  exposing  if 
possible  also,  by  opening  up  floors,  the  infested  joists  beneath,  and 
spreading  out  the  books  and  opening  cases  and  wardrobes.  For  descrip- 
tion of  the  use  of  hydrocyanic-acid  gas  see  Circular  No.  46  of  this  series. 
It  is  very  rarely  possible  to  find  and  destroy  the  external  colony,  and  if 
the  remedies  noted  are  not  feasible  or  prove  ineffective  there  is  no  other 
course  but  to  replace  the  foundation  of  the  buildings  with  walls  and 
floorings  of  stone,  concrete,  or  other  form  of  rock  composition.  In  the 
case  of  the  National  Museum  building  in  Washington  and  several  pri- 
vate edifices  this  course  was  finally  adopted,  with  the  result  that  white 
ants  were  completely  excluded  and  their  work  terminated. 

Approved  : 

James  Wilson, 

Secretary  of  Agriculture. 

Washington,  D.  C,  December  30,  1907.  A(i „ 

O 


